Add structs DecryptedNote, EncryptedNote and HiddenNote

This makes some invalid states unrepresentable, which is something that is desired in this application to reduce mental complexity and to reduce the risk of undesired behaviour of aplying functions like `encrypt` on already encrypted notes.

`Note` is now an enum that holds the structs. This approach is similar to the one used in some parts of `std`, though in this case other approaches could be used, but they would be way too much verbose for this use case.

This change was done because having functions like `hide` on already hidden functions is not a good idea (even if was they do is "just" cloning the structure...).

There are some rough edges, but I'll improve them in another moment.

src/main.rs

@@ -15,7 +15,7 @@ use egui::{Color32, Context, RichText, TextEdit, Widget, WidgetText};
 use log::info;
 use native_dialog::MessageDialog;
 use simple_logger::SimpleLogger;
-use crate::notes::{Note, NoteMetadata};
+use crate::notes::{DecryptedNote, Note, NoteMetadata};
 use crate::password::{check_password, entropy, generate_new_password, migrate_to_password_v1, PasswordSystem};
 use crate::saving::Saving;
 
@@ -108,6 +108,8 @@ impl eframe::App for App {
 
         if !self.tested_password && self.password.is_some() {
             if let Some(note) = self.notes.get(0) {
+                match note {
+                    Note::Encrypted(note) => {
                         if let Ok(password) = check_password(self.password.as_ref().unwrap(), note) {
                             match password {
                                 PasswordSystem::V0(password) => {
@@ -135,6 +137,9 @@ impl eframe::App for App {
                             self.tested_password = false;
                             return;
                         }
+                    }
+                    _ => unreachable!()
+                }
             } else {
                 self.password = Some(generate_new_password(self.password.as_ref().unwrap()))
             }
@@ -245,7 +250,7 @@ impl eframe::App for App {
                                         .then_some(metadata)
                                 });
 
-                            let note = Note::Decrypted {
+                            let note = Note::Decrypted(DecryptedNote {
                                 id: SystemTime::now()
                                     .duration_since(SystemTime::UNIX_EPOCH)
                                     .unwrap()
@@ -257,9 +262,9 @@ impl eframe::App for App {
                                     arbitrary: metadata,
                                 },
                                 text: self.text_buffer.clone(),
-                            };
+                            });
 
-                            self.saving.save_note(note.clone(), password).unwrap();
+                            self.saving.save_note(&note.clone(), password).unwrap();
 
                             let mut vec_deque = VecDeque::from(self.notes.clone());
                             vec_deque.push_front(note);
@@ -353,7 +358,10 @@ impl eframe::App for App {
                             if let Some(save_path) = save_path {
                                let notes: Vec<Note> = self.notes.clone()
                                     .iter()
-                                    .map(|note| note.decrypt(password).expect("failed to decrypt note"))
+                                    .map(|note| match note {
+                                        Note::Encrypted(note) => note.decrypt(password).expect("failed to decrypt note").into(),
+                                        _ => note.clone(),
+                                    })
                                     .collect();
 
                                 let json_notes = serde_json::to_string(&notes).unwrap();

src/notes/mod.rs

@@ -13,124 +13,132 @@ pub struct NoteMetadata {
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
-pub enum Note {
+pub struct EncryptedNote {
-    Encrypted {
+    pub id: String,
-        id: String,
+    pub title: String,
-        title: String,
+    pub metadata: NoteMetadata,
-        metadata: NoteMetadata,
+    pub encrypted_text: String,
-        encrypted_text: String,
-    },
-    Decrypted {
-        id: String,
-        title: String,
-        metadata: NoteMetadata,
-        text: String,
-    },
-    Hidden {
-        id: String,
-        title: String,
-        metadata: NoteMetadata,
-        text: String,
-    }
 }
 
-impl Note {
+#[derive(Debug, Clone, Serialize, Deserialize)]
-    pub fn encrypt(&self, password: &str) -> anyhow::Result<Self> {
+pub struct DecryptedNote {
+    pub id: String,
+    pub title: String,
+    pub metadata: NoteMetadata,
+    pub text: String,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct HiddenNote(pub DecryptedNote);
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub enum Note {
+    Encrypted(EncryptedNote),
+    Decrypted(DecryptedNote),
+    Hidden(HiddenNote),
+}
+
+impl DecryptedNote {
+    pub fn encrypt(&self, password: &str) -> anyhow::Result<EncryptedNote> {
         let mut rng = rand::thread_rng();
 
-        match self {
-            Note::Decrypted { id, text, metadata, title } => {
         let pwbox = Sodium::build_box(&mut rng)
-                    .seal(password.to_string().into_bytes(), text.clone().into_bytes())?;
+            .seal(password.to_string().into_bytes(), self.text.clone().into_bytes())?;
 
         let mut eraser = Eraser::new();
         eraser.add_suite::<Sodium>();
         let erased: ErasedPwBox = eraser.erase(&pwbox)?;
 
-                Ok(Self::Encrypted {
+        Ok(EncryptedNote {
-                    id: id.clone(),
+            id: self.id.clone(),
-                    title: title.clone(),
+            title: self.title.clone(),
-                    metadata: metadata.clone(),
+            metadata: self.metadata.clone(),
             encrypted_text: serde_json::to_string(&erased)?,
         })
     }
-            _ => Ok(self.clone()),
-        }
-    }
 
-    pub fn decrypt(&self, password: &str) -> anyhow::Result<Self> {
+    pub fn hide(self) -> HiddenNote {
-        match self {
+        HiddenNote(self)
-            Note::Encrypted { id, title, metadata, encrypted_text } => {
+    }
+}
+
+impl EncryptedNote {
+    pub fn decrypt(&self, password: &str) -> anyhow::Result<DecryptedNote> {
         let mut eraser = Eraser::new();
         eraser.add_suite::<Sodium>();
-                let erased: ErasedPwBox = serde_json::from_str(encrypted_text)?;
+        let erased: ErasedPwBox = serde_json::from_str(&self.encrypted_text)?;
 
         let decrypted_bytes = eraser.restore(&erased)?.open(password)?.to_vec();
         let decrypted_text = String::from_utf8(decrypted_bytes)?;
 
-                Ok(Self::Decrypted {
+        Ok(DecryptedNote {
-                    id: id.clone(),
+            id: self.id.clone(),
-                    title: title.clone(),
+            title: self.title.clone(),
-                    metadata: metadata.clone(),
+            metadata: self.metadata.clone(),
             text: decrypted_text,
         })
     }
-            _ => Ok(self.clone()),
+}
-        }
-    }
 
-    pub fn hide(self) -> Self {
+impl HiddenNote {
-        match self {
+    pub fn unhide(self) -> DecryptedNote {
-            Note::Decrypted { id, title, metadata, text } => {
+        self.0
-                Self::Hidden { id, title, metadata, text }
-            }
-            _ => unreachable!()
-        }
     }
+}
 
-    pub fn unhide(self) -> Self {
+impl From<HiddenNote> for Note {
-        match self {
+    fn from(value: HiddenNote) -> Self {
-            Note::Hidden { id, title, metadata, text } => {
+        Self::Hidden(value)
-                Self::Decrypted { id, title, metadata, text }
-            }
-            _ => unreachable!()
-        }
     }
+}
 
+impl From<DecryptedNote> for Note {
+    fn from(value: DecryptedNote) -> Self {
+        Self::Decrypted(value)
+    }
+}
+
+impl From<EncryptedNote> for Note {
+    fn from(value: EncryptedNote) -> Self {
+        Self::Encrypted(value)
+    }
+}
+
+impl Note {
     pub fn render(&self, ui: &mut Ui, password: &str, cb: impl FnOnce(String)) -> Option<Self> {
         let mut value = None;
         ui.group(|ui| {
             match self {
-                Note::Encrypted { id, title, metadata, .. } => {
+                Note::Encrypted(note) => {
-                    let result = render_title_and_metadata(ui, title, metadata, false, None);
+                    let result = render_title_and_metadata(ui, &note.title, &note.metadata, false, None);
                     if let Some(action) = result {
                         match action {
-                            NoteRenderAction::Delete => cb(id.to_string()),
+                            NoteRenderAction::Delete => cb(note.id.to_string()),
                             _ => unreachable!()
                         }
                     }
                     if ui.button("decrypt note").clicked() {
-                        value = Some(self.decrypt(password).unwrap());
+                        value = Some(note.decrypt(password).unwrap().into());
                     }
                 }
-                Note::Decrypted { id, title, metadata, text, .. } => {
+                Note::Decrypted(note) => {
-                    let result = render_title_and_metadata(ui, title, metadata, true, Some(ButtonType::Hide));
+                    let result = render_title_and_metadata(ui, &note.title, &note.metadata, true, Some(ButtonType::Hide));
                     if let Some(action) = result {
                         match action {
-                            NoteRenderAction::Delete => cb(id.to_string()),
+                            NoteRenderAction::Delete => cb(note.id.to_string()),
-                            NoteRenderAction::Hide => value = Some(self.clone().hide()),
+                            NoteRenderAction::Hide => value = Some(note.clone().hide().into()),
                             _ => unreachable!()
                         }
                     }
 
-                    ui.label(text);
+                    ui.label(&note.text);
                 }
-                Note::Hidden { id, title, metadata, .. } => {
+                Note::Hidden(note) => {
-                    let result = render_title_and_metadata(ui, title, metadata, true, Some(ButtonType::Unhide));
+                    let result = render_title_and_metadata(ui, &note.0.title, &note.0.metadata, true, Some(ButtonType::Unhide));
                     if let Some(action) = result {
                         match action {
-                            NoteRenderAction::Delete => cb(id.to_string()),
+                            NoteRenderAction::Delete => cb(note.0.id.to_string()),
-                            NoteRenderAction::Unhide => value = Some(self.clone().unhide()),
+                            NoteRenderAction::Unhide => value = Some(note.clone().unhide().into()),
                             _ => unreachable!()
                         }
                     }
@@ -142,14 +150,6 @@ impl Note {
 
         value
     }
-
-    pub fn id(&self) -> String {
-        match self {
-            Note::Encrypted { id, .. } => id.clone(),
-            Note::Decrypted { id, .. } => id.clone(),
-            Note::Hidden { id, .. } => id.clone(),
-        }
-    }
 }
 
 enum NoteRenderAction {

src/password/mod.rs

@@ -1,7 +1,7 @@
 use anyhow::bail;
 use argon2::Argon2;
 use sha2::{Sha256, Digest};
-use crate::notes::Note;
+use crate::notes::{EncryptedNote, Note};
 use crate::saving::Saving;
 
 pub fn generate_new_password(password: &str) -> String {
@@ -35,7 +35,7 @@ pub enum PasswordSystem {
     V1(String),
 }
 
-pub fn check_password(password: &str, note: &Note) -> anyhow::Result<PasswordSystem> {
+pub fn check_password(password: &str, note: &EncryptedNote) -> anyhow::Result<PasswordSystem> {
     if note.decrypt(password).is_err() {
         let new_password = generate_new_password(password);
         if note.decrypt(&new_password).is_err() {
@@ -59,7 +59,6 @@ fn hash_password(password: &[u8], output: &mut [u8]) {
 pub fn migrate_to_password_v1(password: &str, notes: &Vec<Note>, saving: &Saving) -> anyhow::Result<String> {
     let new_password = generate_new_password(password);
     for note in notes {
-        let note = note.decrypt(password)?;
         saving.save_note(note, &new_password)?;
     }
 

src/saving/mod.rs

@@ -30,10 +30,15 @@ impl Saving {
         Ok(notes.into())
     }
 
-    pub fn save_note(&self, note: Note, password: &str) -> anyhow::Result<()> {
+    pub fn save_note(&self, note: &Note, password: &str) -> anyhow::Result<()> {
-        let note = note.encrypt(password)?;
+        let note = match note {
+            Note::Encrypted(note) => note.clone(),
+            Note::Decrypted(note) => note.encrypt(password)?,
+            Note::Hidden(note) => note.0.encrypt(password)?,
+        };
+
         let mut path = self.path.clone().join("_");
-        path.set_file_name(format!("{}.json", note.id()));
+        path.set_file_name(format!("{}.json", note.id));
 
         fs::write(path, serde_json::to_string(&note)?)?;